<html>
    <head>
        <title>Test</title>
        <style>

          body { flow:stack; }
          body > widget { 
            background: linear-gradient(to right, gold , brown); size:*; }
          body > overlay { 
            display:block;
            behavior:windowed;
            background: rgba(0,255,0,0.15); border-radius:10dip; size:0.5*; margin:0.25*; }

        </style>
        <script type="text/tiscript"></script>
    </head>
    <body>
       <widget>custom child window (placeholder for now)</widget>
       <overlay>Overlay (window)</overlay>
    </body>
</html>